Analysis on Influence of Effective Turbulence Intensity on Blade Root Fatigue Load of WTGS

2012 ◽  
Vol 538-541 ◽  
pp. 605-609
Author(s):  
Feng Gai ◽  
An Min Cai ◽  
Da Tong Zhang ◽  
Li Xiang Sun
Keyword(s):  
Wind Speed ◽  
Turbulence Intensity ◽  
Theoretical Basis ◽  
Fatigue Load ◽  
Blade Root ◽  
Type Selection ◽  
Air Density ◽  
Damage Theory ◽  
Fatigue Loads ◽  
Cumulative Fatigue Damage

Based on the Palmgren-Miner linear cumulative fatigue damage theory, the blade root fatigue loads in different effective turbulence intensities were calculated and analysed. The results show that when the air density and the wind speed are constant, the blade root fatigue loads increase linearly with the effective turbulence intensity increasing, and the slopes increase linearly with the wind speed increasing. According to these results, the main source of the blade root fatigue loads under different wind conditions can be estimated to provide a theoretical basis for WTGS type selection in the special sites.

Research the Influencing Factors of the Low Wind Speed Wind Turbine Fatigue Loads

2014 ◽  
Vol 1008-1009 ◽  
pp. 164-168
Author(s):  
Fa Ming Wu ◽  
Lei Wang ◽  
Dian Wang ◽  
Jia Bao Jing
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Turbulence Intensity ◽  
Fatigue Load ◽  
Annual Average ◽  
Average Wind Speed ◽  
Low Wind Speed ◽  
Air Density ◽  
Average Wind ◽  
Fatigue Loads

This paper analyzes three main factors (turbulence intensity, air density, annual average wind speed ) that influence the low wind speed wind turbine fatigue loads, In order to analyze the influence of each main parameters how to affect the fatigue load of low wind speed wind turbine, using a 2000kW wind turbine as an example on the simulation test , 3 turbulence, 4 air density and 7 annual average wind speed were employed. The results show that, with the air density, turbulence intensity and the annual average wind speed increases, the wind turbine of fatigue load increase in rule approximately. Based on the above rule, it can reduce fatigue loads and prolong the life of wind turbine in design optimization of low wind speed wind turbine and sit choice.

Research of the Analysis Method on the Three Basics of the Wind Turbine Fatigue Loads

2014 ◽  
Vol 953-954 ◽  
pp. 432-436
Author(s):  
Lei Wang ◽  
Fa Ming Wu ◽  
Dian Wang
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Turbulence Intensity ◽  
Analysis Method ◽  
It Use ◽  
Air Density ◽  
Loads Analysis ◽  
Fatigue Loads ◽  
Wind Resources

The research has identified turbulence intensity, annual wind speed and air density as the three basics of fatigue loads, in this paper, we call it three basics for short. This paper presents a method to analyze the three basics of the wind turbine fatigue loads. It explains the fatigue loads analysis idea and method of the three basics and it use the analysis method to research the extent of the influence by using a 1650kW wind turbine as an example. It can be seen from the results that the wind resources increase one classification, the influence of the turbulence intensity is the greatest, then the annual wind speed, finally the air density.

scholarly journals More accurate aeroelastic wind-turbine load simulations using detailed inflow information

2018 ◽  
Author(s):  
Mads Mølgaard Pedersen ◽  
Torben Juul Larsen ◽  
Helge Aagaard Madsen ◽  
Gunner Christian Larsen
Keyword(s):  
Wind Speed ◽  
Turbulence Intensity ◽  
Atmospheric Stability ◽  
Pitot Tube ◽  
Aerodynamic Model ◽  
Mean Wind Speed ◽  
Fatigue Loads ◽  
Aeroelastic Simulations ◽  
The One ◽  
Measured Wind Speed

Abstract. In this paper, inflow information is extracted from a measurement database and used for aeroelastic simulations to investigate if using more accurate inflow descriptions improves the accuracy of the simulated fatigue loads. The inflow information is extracted from the nearby met masts and a blade-mounted five-hole pitot tube. The met masts provide measurements of the inflow at fixed positions some distance away, whereas the pitot tube measures the inflow while rotating with the rotor. The met mast measures the free-inflow velocity, but the measured turbulence may evolve on its way to the turbine, pass besides the turbine, or the mast may be in the wake of the turbine. The inflow measured by the pitot tube, on the other hand, is very representative of the wind that acts on the turbine as it is measured close to the blades and includes variations within the rotor plane. This inflow is, however, affected by the presence of the turbine, and therefore an aerodynamic model is used to estimate the free-inflow velocities that would have been at the same time and position without the presence of the turbine. The inflow information used for the simulations includes the mean wind speed and trend, the turbulence intensity, wind shear profile, atmospheric stability dependent turbulence parameters, and azimuthal variations within the rotor plane. In addition, the instantly measured wind speed is used to constrain the turbulence. It is concluded that the period-specific turbulence intensity must be included in the aeroelastic simulations to make the range of the simulated fatigue loads representative for the range of the measured fatigue loads. Furthermore, it is found that the one-to-one correspondence between the measured and simulated fatigue loads is improved considerably by using inflow characteristics extracted from the pitot tube instead of the met-mast-based sensors as input for the simulations. Finally, the use of pitot-tube wind speed to constrain the turbulence is found to decrease the variation of the simulated loads due to different turbulence realisations (seeds), such that the need for multiple simulations is reduced.

scholarly journals Characterising Turbulence Intensity for Fatigue Load Analysis of Wind Turbines

2005 ◽  
Vol 29 (4) ◽  
pp. 319-329 ◽  
Author(s):  
Kurt S. Hansen ◽  
Gunner Chr. Larsen
Keyword(s):  
Wind Speed ◽  
Wind Turbines ◽  
Turbulence Intensity ◽  
Cost Reduction ◽  
Fatigue Loading ◽  
Fatigue Load ◽  
Wind Characteristics ◽  
Load Analysis ◽  
Dynamic Structures ◽  
Turbine Design

Turbulence in wind velocity presents a major factor for modern wind turbine design as cost reduction as are sort for the dynamic structures. Therefore this paper contains a parametrisation of the turbulence intensity at given sites, relevant for the calculation of fatigue loading of wind turbines. The parameterisation is based on wind speed measurements extracted from the “Database on Wind Characteristics” ( www.winddata.com ). The parameterisation is based on the LogNormal distribution, which has proven to be suitable distribution to describe the turbulence intensity distribution.

scholarly journals More accurate aeroelastic wind-turbine load simulations using detailed inflow information

2019 ◽  
Vol 4 (2) ◽  
pp. 303-323
Author(s):  
Mads Mølgaard Pedersen ◽  
Torben Juul Larsen ◽  
Helge Aagaard Madsen ◽  
Gunner Christian Larsen
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Turbulence Intensity ◽  
Atmospheric Stability ◽  
Pitot Tube ◽  
Wind Speeds ◽  
Inflow Turbulence ◽  
Mean Wind Speed ◽  
Fatigue Loads ◽  
Aeroelastic Simulations

Abstract. In this paper, inflow information is extracted from a measurement database and used for aeroelastic simulations to investigate if using more accurate inflow descriptions improves the accuracy of the simulated wind-turbine fatigue loads. The inflow information is extracted from nearby meteorological masts (met masts) and a blade-mounted five-hole pitot tube. The met masts provide measurements of the inflow at fixed positions some distance away from the turbine, whereas the pitot tube measures the inflow while rotating with the rotor. The met mast measures the free-inflow velocity; however the measured turbulence may evolve on its way to the turbine, pass beside the turbine or the mast may be in the wake of the turbine. The inflow measured by the pitot tube, in comparison, is very representative of the wind that acts on the turbine, as it is measured close to the blades and also includes variations within the rotor plane. Nevertheless, this inflow is affected by the presence of the turbine; therefore, an aerodynamic model is used to estimate the free-inflow velocities that would have occurred at the same time and position without the presence of the turbine. The inflow information used for the simulations includes the mean wind speed field and trend, the turbulence intensity, the wind-speed shear profile, atmospheric stability-dependent turbulence parameters, and the azimuthal variations within the rotor plane. In addition, instantaneously measured wind speeds are used to constrain the turbulence. It is concluded that the period-specific turbulence intensity must be used in the aeroelastic simulations to make the range of the simulated fatigue loads representative for the range of the measured fatigue loads. Furthermore, it is found that the one-to-one correspondence between the measured and simulated fatigue loads is improved considerably by using inflow characteristics extracted from the pitot tube instead of using the met-mast-based sensors as input for the simulations. Finally, the use of pitot-tube-recorded wind speeds to constrain the inflow turbulence is found to significantly decrease the variation of the simulated loads due to different turbulence realizations (seeds), whereby the need for multiple simulations is reduced.

scholarly journals Thermal Performance Analysis of Heat Collection Wall in High-Rise Building Based on the Measurement of Near-Wall Microclimate

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 2023
Author(s):  
Ruixin Li ◽  
Yiwan Zhao ◽  
Gaochong Lv ◽  
Weilin Li ◽  
Jiayin Zhu ◽  
...  
Keyword(s):  
Wind Speed ◽  
Structural Design ◽  
Theoretical Basis ◽  
Thermal Process ◽  
Measured Data ◽  
Passive Heating ◽  
High Rise ◽  
And Performance ◽  
Wall Components ◽  
Near Wall

Near-wall microenvironment of a building refers to parameters such as wind speed, temperature, relative humidity, solar radiation near the building’s façade, etc. The distribution of these parameters on the building façade shows a certain variation based on changes in height. As a technology of passive heating and ventilation, the effectiveness of this application on heat collection wall is significantly affected by the near-wall microclimate, which is manifested by the differences, and rules of the thermal process of the components present at different elevations. To explore the feasibility and specificity of this application of heat collection wall in high-rise buildings, this study uses three typical high-rise buildings from Zhengzhou, China, as research buildings. Periodic measurements of the near-wall microclimate during winter and summer were carried out, and the changing rules of vertical and horizontal microclimate were discussed in detail. Later, by combining these measured data with numerical method, thermal process and performance of heat collection wall based on increasing altitude were quantitatively analyzed through numerical calculations, and the optimum scheme for heat collection wall components was summarized to provide a theoretical basis for the structural design of heat-collecting wall in high-rise buildings.

scholarly journals Airflow Characteristics According to the Change in the Height and Porous Rate of Building Roofs for Efficient Installation of Small Wind Power Generators

2021 ◽  
Vol 13 (10) ◽  
pp. 5688
Author(s):  
Jangyoul You ◽  
Kipyo You ◽  
Minwoo Park ◽  
Changhee Lee
Keyword(s):  
Wind Speed ◽  
Wind Power ◽  
Turbulence Intensity ◽  
Flow Characteristics ◽  
High Porosity ◽  
Power Generators ◽  
Speed Reduction ◽  
Reduction Effect ◽  
Wind Power Generators ◽  
The Impact

In this paper, the air flow characteristics and the impact of wind power generators were analyzed according to the porosity and height of the parapet installed in the rooftop layer. The wind speed at the top was decreasing as the parapet was installed. However, the wind speed reduction effect was decreasing as the porosity rate increased. In addition, the increase in porosity significantly reduced turbulence intensity and reduced it by up to 40% compared to no railing. In the case of parapets with sufficient porosity, the effect of reducing turbulence intensity was also increased as the height increased. Therefore, it was confirmed that sufficient parapet height and high porosity reduce the effect of reducing wind speed by parapets and significantly reducing the turbulence intensity, which can provide homogeneous wind speed during installation of wind power generators.

scholarly journals Wind Turbulence Intensity at La Ventosa, Mexico: A Comparative Study with the IEC61400 Standards

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3007 ◽  
Author(s):  
C. Lopez-Villalobos ◽  
O. Rodriguez-Hernandez ◽  
R. Campos-Amezcua ◽  
Guillermo Hernandez-Cruz ◽  
O. Jaramillo ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Turbines ◽  
Turbulence Intensity ◽  
Structural Damage ◽  
Atmospheric Stability ◽  
Design Parameters ◽  
Power Sector ◽  
Wind Speeds ◽  
Technical Solutions ◽  
Large Wind

Wind speed turbulence intensity is a crucial parameter in designing the structure of wind turbines. The IEC61400 considers the Normal Turbulence Model (NTM) as a reference for fatigue load calculations for small and large wind turbines. La Ventosa is a relevant region for the development of the wind power sector in Mexico. However, in the literature, there are no studies on this important parameter in this zone. Therefore, we present an analysis of the turbulence intensity to improve the understanding of local winds and contribute to the development of reliable technical solutions. In this work, we experimentally estimate the turbulence intensity of the region and the wind shear exponent in terms of atmospheric stability to analyze the relation of these design parameters with the recommended standard for large and small wind turbines. The results showed that the atmosphere is strongly convective and stable in most of the eleven months studied. The turbulence intensity analysis showed that for a range of wind speeds between 2 and 24 m/s, some values of the variable measured were greater than those recommended by the standard, which corresponds to 388 hours of turbulence intensity being underestimated. This may lead to fatigue loads and cause structural damage to the technologies installed in the zone if they were not designed to operate in these wind speed conditions.

scholarly journals Lidar arc scan uncertainty reduction through scanning geometry optimization

2016 ◽  
Vol 9 (4) ◽  
pp. 1653-1669 ◽  
Author(s):  
Hui Wang ◽  
Rebecca J. Barthelmie ◽  
Sara C. Pryor ◽  
Gareth. Brown
Keyword(s):  
Theoretical Model ◽  
Wind Speed ◽  
Wind Energy ◽  
Turbulence Intensity ◽  
Wind Direction ◽  
Energy Production ◽  
Elevation Angle ◽  
Relative Standard Error ◽  
Power Performance ◽  
Relative Standard

Abstract. Doppler lidars are frequently operated in a mode referred to as arc scans, wherein the lidar beam scans across a sector with a fixed elevation angle and the resulting measurements are used to derive an estimate of the n minute horizontal mean wind velocity (speed and direction). Previous studies have shown that the uncertainty in the measured wind speed originates from turbulent wind fluctuations and depends on the scan geometry (the arc span and the arc orientation). This paper is designed to provide guidance on optimal scan geometries for two key applications in the wind energy industry: wind turbine power performance analysis and annual energy production prediction. We present a quantitative analysis of the retrieved wind speed uncertainty derived using a theoretical model with the assumption of isotropic and frozen turbulence, and observations from three sites that are onshore with flat terrain, onshore with complex terrain and offshore, respectively. The results from both the theoretical model and observations show that the uncertainty is scaled with the turbulence intensity such that the relative standard error on the 10 min mean wind speed is about 30 % of the turbulence intensity. The uncertainty in both retrieved wind speeds and derived wind energy production estimates can be reduced by aligning lidar beams with the dominant wind direction, increasing the arc span and lowering the number of beams per arc scan. Large arc spans should be used at sites with high turbulence intensity and/or large wind direction variation.

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